Our previous research established the pattern of acquisition of cell surface receptors during normal human myeloid differentiation. These membrane markers, now being used to examine leukemic myeloid differentiation are detected on cells from only a minority of patients. The objectives of this proposed research are: (1) To induce differentiation in freshly isolated human acute nonlymphoid leukemic cells (ANLL) by incubation with known inducers of differentiation and examine cells for differentiation, viability and recovery; (2) to assess differentiation by cell surface markers for IgG and complement, morphology, and cytochemistry; (3) to investigate whether 5'-nucleotidase and microviscosity can be used as new markers of myeloid membrane maturation; (4) to induce membrane differentiation using HL-60 cells (a human acute promyelocytic leukemia cell line) and clone these cells to examine the mechanism of induced membrane marker expression; (5) to investigate whether chemotherapeutic drugs also will induce differentiation in both HL-60 and freshly isolated leukemic cells; (6) to compare in vitro induction of differentiation to in vivo effects using a diffusion chamber technique in mice; and (7) to compare in vitro chemotherapeutic results with in vivo clinical response in patients receiving the same agents. The overall objective of this research is to provide a useful in vitro model to aid in the diagnosis, treatment, and prognosis of ANLL.